Study on the Process of Preparing Nickel-Iron Alloy by Hydrogen Selective Reduction

Recycling of nickel metal from nickel-containing spent catalysts can not only alleviate the contradiction between supply and demand, but also guarantee the demand of national strategic reserve metal, which is of great strategic significance. With reference to the gas-based shaft furnace-electric furnace short flow process in iron and steel metallurgy, this study proposes to treat nickel-containing waste catalysts with hydrogen as a reducing agent and to prepare nickel-iron alloys by using high-temperature melting process. The mechanism of selective reduction of Ni in waste catalysts by hydrogen was investigated by simulation analysis, NiO will react rapidly with hydrogen at lower temperatures to produce Ni, and the reduction of Fe2O3 is greatly affected by the temperature and the reaction is a cascade reaction of Fe2O3, Fe3O4, FeO, Fe. Under the conditions of hydrogen concentration of 60vol.%, reduction temperature of 800 ℃, reduction time of 90 min, and pellet diameter size of 10 mm, the metallization rates of Ni and Fe reached 92% and 50%, respectively.Under the conditions of melting temperature of 1500 ℃, melting time of 4 h, iron trapping agent addition of 12% of the mass of raw materials, and carbon reducing agent addition of 4% of the mass of raw materials, the recovery rate of nickel in the spent catalyst reached 99%. Recycling requirements have been met. This study provides an efficient recovery method for the enrichment of metallic nickel by high-temperature smelting